GEMMA - Environmental Engineering and Microbiology Research Group, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya·BarcelonaTech, c/ Jordi Girona 1-3, Building D1, 08034, Barcelona, Spain; GHS - Dept. of Civil and Environmental Engineering, Universitat Politècnica de Catalunya, Jordi Girona 1-3, 08034, Barcelona, Spain.
GEMMA - Environmental Engineering and Microbiology Research Group, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya·BarcelonaTech, c/ Jordi Girona 1-3, Building D1, 08034, Barcelona, Spain.
Chemosphere. 2022 Jan;287(Pt 4):132383. doi: 10.1016/j.chemosphere.2021.132383. Epub 2021 Sep 27.
Treatment wetlands (TW) operated as bioelectrochemical systems (BES-TW) provide a higher degree of treatment than conventional TW. Yet, the fundamental processes or mechanisms for the envisaged better performance of BES-TW over conventional TW remains poorly understood. This work aimed to determine to which extent microbial activity enhancement could be the reason behind this treatment performance increase. To this purpose, pilot-scale horizontal sub-surface flow BES-TW operated under three different configurations were continuously fed with real urban wastewater. BES-TW were evaluated for COD and ammonia removal efficiency, and two techniques of microbial activity assessment were applied. Configurations, tested in duplicate, were: control TWs without electrodes (C-TW), TWs operated as microbial fuel cells (MFC-TW), and TWs operated as microbial electrolysis cells (MEC-TW). Microbial activity was assessed by measuring the enzymatic activity (EA) (FDA hydrolysis technique) and the aerobic activity (AA) (estimated through respirometry). Results showed that BES-TW outperformed C-TW in terms of both microbial activity enhancement and contaminants removal efficiency, especially in the case of MEC-TW. More precisely, this configuration showed an average improvement of 17%, and 56% in COD removal and EA efficiencies, respectively, compared to C-TW. Regarding AA activity, although MEC-TW seemed to outperform the rest of the configurations, differences were not statistically significant. This work demonstrates that TWs operated as BES increase the overall enzymatic activity of the treatment bed and this, in turn, is the leading cause to a higher degree of treatment performance.
处理湿地（TW）作为生物电化学系统（BES-TW）运行时提供比传统 TW 更高程度的处理。然而，对于 BES-TW 相对于传统 TW 的预期更好性能的基本过程或机制仍了解甚少。这项工作旨在确定微生物活性增强在多大程度上可能是这种处理性能提高的原因。为此，采用三种不同配置的中试规模水平潜流 BES-TW 连续处理实际城市废水。评估了 BES-TW 的 COD 和氨氮去除效率，并应用了两种微生物活性评估技术。在平行试验中测试的配置有：没有电极的对照 TW（C-TW）、作为微生物燃料电池（MFC-TW）运行的 TW 和作为微生物电解池（MEC-TW）运行的 TW。通过测量酶活性（EA）（FDA 水解技术）和有氧活性（AA）（通过呼吸计估计）来评估微生物活性。结果表明，BES-TW 在微生物活性增强和污染物去除效率方面均优于 C-TW，尤其是在 MEC-TW 的情况下。更准确地说，与 C-TW 相比，该配置在 COD 去除和 EA 效率方面分别平均提高了 17%和 56%。关于 AA 活性，尽管 MEC-TW 似乎优于其他配置，但差异没有统计学意义。这项工作表明，作为 BES 运行的 TW 增加了处理床的整体酶活性，而这反过来又是更高处理性能的主要原因。
